Direct drive casing hanger apparatus

ABSTRACT

Well bore casing hanger apparatus in which a hanger body has a pack-off or seal structure threadedly mounted thereon, the seal structure also being threadedly connected to a lower portion of a running tool swivelly related to an upper portion of the running tool, the upper running tool portion being secured to a running string for lowering the apparatus to bring its body into engagement with a seat within an underwater wellhead housing, at which time a fluid circulation path or passage between the body and housing is open. The upper running string portion is rotated to thread the seal structure downwardly along the body to passage-closing position and to also unthread the seal structure from the lower running tool portion, which permits the running string and running tool to be elevated from the hanger apparatus and withdrawn to the drilling rig.

iJitere atrtt H51 396389725 Ahlstone 1 Feb. 1, 1972 541 eraser emvsCASING HANGER 3,468,559 9/1969 Ahlstone ..l66/87 APPAATUS 3,492,0261/1970 Ahlstone 166/87 [72] Inventor: Arthur G. Ahlstone, Ventura,Calif. primary E i j Leppink [73] Assignee: Vetco Offshore Industries,1nc., Ventura, Knegel Calif.

[57] ABSTRACT [22] Filed: May 15, 1970 Well bore casing hanger apparatusin which a hanger body has PP 379527 a pack-ofi or seal structurethreadedly mounted thereon, the

seal structure also being threadedly connected to a lower por- [52] UsCl 166/226 166/87 tion of a running tool swivelly related to an upperportion of "Enb 33/00 the running too], the upper running tool portionbeing secured M166, 87 88 89 1 15 224 to a running string for loweringthe apparatus to bring its body 166/226 5 1 into engagement with a seatwithin an underwater wellhead housing, at which time a fluid circulationpath or passage [51] 1nLC1 [58] Field of Search r between the body andhousing is open. The upper running [50} References Cited string portionis rotated to thread the seal structure UNITED STATES PATENTS downwardlyalong the body to passage-closing position and to also unthread the sealstructure from the lower running tool 3,273,646 9/1966 Walker ..166/88portion, which permits the running String and running too] to 3,279,53910/1966 9 at "166/88 be elevated from the hanger apparatus and withdrawnto the 3,335,799 8/1967 Miller drilling rig 16 Claims, 9 Drawing FiguresPATENTEU FEB 1 I972 SHEET 1 [IF d I/vvE/vroe PATENTED FEB 1 I 2 SHEET 3[IF 4 .Z'N vs/vroe arm/1e STONE 5M1 my DIRECT DRIVE CASING HANGERAPPARATUS During the drilling of subsea or other underwater wells, mostsubsea casing hanger systems require that the hanger and pack-offassembly or seal structure be run separately. Some casing hanger systemsprovide for the running of the hanger and seal structure together, but aseparate round trip of a sealactuating tool is required to energize theseal and to permit its testing. The rig time required for the extraround trip is very costly to the operator for whom the work is beingdone, the cost presently ranging from about $500 to $1,000 per hour, theextra round trip usually requiring several hours at a minimum. If thepack-off is not installed properly and tested before the cement slurryhas had an opportunity of setting up, it might become impossible tosecure an appropriate seal closing the passage between the casing hangerbody and a surrounding hanger housing in which it is set, whichsometimes results in the loss of the well. It is desirable to actuatethe pack-off assembly immediately upon completion of the cementingoperation so that the seal can be energized and tested within minutesafter the cementing operation has been completed.

Actuation of the pack-off assembly and its testing has been proposedheretofore (see, for example, U.S. Pat. Nos. 3,335,799 and 3,492,026).The last-mentioned patent is illustrative of apparatus now beingemployed. However, such apparatus requires the provision of bypassgrooves and/or bypass ports in the wellhead housing, which are expensiveand costly to manufacture.

By virtue of the present invention, the casing hanger body and pack-offassembly or seal structure are lowered as a unit from a drilling rig ona running tool with a running string attached thereto, and with thecasing string secured to and depending from the body. The entireorganization is lowered until the body and seal structure move into asurrounding wellhead housing, the body engaging a seat in the wellheadhousing. At this time, a circulating passage between the body andwellhead housing is in open condition, permitting fluid to be circulateddown through the casing string and up around the well bore annulussurrounding it, followed by the performance of the operation ofcementing the casing string in the well bore, the cement usually beingdisplaced in such quantities as to rise into the circulation passage.The seal assembly is actuated to shift it into its circulation passageclosing position, and, at the same time, the running tool is releasedfrom the seal assembly and the casing hanger body. With the running toolstill in sealing relation to the casing hanger body, the pack-off of theseal structure can be tested to insure against its leaking. If leakingdoes occur, the running tool can still be actuated to increase thepackolf force to insure the complete effectiveness of the seal assembly.

Accordingly, an object of the invention is to provide a casing hangerapparatus in which the hanger body and seal structure are lowered in thewell bore together on the running string, and in which the runningstring is actuated for the purpose of shifting the seal structure to itsposition closing the circulation passage between the hanger body and asurrounding wellhead housing or body, and also to release the runningtool from the hanger body, thereby performing both operations with asingle round trip.

Another object of the invention is to provide an apparatus of the abovetype, which is of simpler construction and less costly to manufacturethan prior devices, such as exemplified by the above two US. Patents.

Yet a further object of the invention is to provide a casing hangerapparatus which renders it comparatively easy to provide the propercasing thread on the hanger body, thereby making it possible to reduceinventories and inventory expenses. More particularly, the exteriors ofall casing hangers to fit within a particular size wellhead housing, andthe pack-off used in conjunction therewith, can be made identical, and,therefore, interchangeable, it only being necessary to change the innershape and easing thread on the hanger body.

Yet a further object of the invention is to provide a casing hangerapparatus which permits easy stacking in any combination in a wellheadhousing, rather than requiring their being landed in a specificsequence, such as presently required with some other types of apparatusnow on the market. A lower casing hanger assembly can provide the seatin the wellhead housing for an upper casing hanger body.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of a formin which it may be embodied. This form is shown in the drawingsaccompanying and forming part of the present specification. It will nowbe described in detail, for the purpose of illustrating the generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in a limiting sense.

Referring to the drawings:

FIGS. la and 1b together constitute a quarter longitudinal sectionthrough casing hanger apparatus embodying the invention, the parts beingillustrated with a circulation passage in open condition, FIG. lb beinga lower continuation of FIG. la;

FIGS. 2a and 2b are views corresponding to FIGS. la and lb with thecirculation passage closed, FIG. 2b being a lower continuation of FIG.2a;

FIG. 3 is a quarter longitudinal section, on a reduced scale,corresponding to FIGS. 2a and 2b, with the running tool removed;

FIGS. 4a and 4b together constitute a quarter longitudinal sectionillustrating a plurality of casing hangers disposed in an outer casingwith circulation passages closed, the uppermost casing hangerssupportinga tubing hanger and depending tubing string, FIG. 4b being alower continuation of FIG. 4a;

FIG. 5 is a cross section, on a reduced scale, taken along the line 5-5on FIG. 2b;

FIG. 6 is an enlarged fragmentary longitudinal section through an upperportion of the apparatus illustrated in F IG, 4a.

As illustrated in the drawings, a wellhead housing 10 is suitablydisposed above a well bore (not shown), which may extend downwardly froman ocean floor (not shown), a suitable pipe string 11 being secured tothe lower end of the housing and extending into the well bore. Thishousing has a downwardly tapering seat 12 therein and a cylindricalinternal surface 13 extending upwardly from such seat to the upper endof the housing.

Casing hanger apparatus 14 is to be lowered from a suitable drillingvessel or platform (not shown) at or above the surface of the body ofwater through which the well bore is to be drilled and completed. Thecasing hanger apparatus includes an inner body 15, having an internalthread 16 to which the upper end of a casing string 17 is threadedlysecured, the casing string being adapted to extend downwardly in thewell bore to the desired depth when the hanger apparatus has beeninstalled in the wellhead housing. The inner body includes a lowerterminal portion 18 adapted to engage the housing seat 12 to enable'thehanger body to support the casing string in the well bore. The body hasa plurality of ports 19 extending therethrough providing a portion of acirculation passage for fluid from the annular space 20 between theinner and outer casing strings ll, 17 to flow into the annulus 21between the external cylindrical seal surface 22 on the hanger bodyimmediately above the body ports 19 and the opposed inner cylindricalseal surface 13 of the wellhead housing 10. The body has an upwardlyfacing seat or shoulder 23 thereon at the lower end of this annularspace, against which a seal structure or pack-off assembly 24 can abutwhen the circulation passage 21 between the casing hanger and housing isto be closed.

The seal structure includes an upper actuator and coupling sleeve 25having an internal thread 26, preferably of righthand, meshing with acompanion external thread 27 on the upper portion 28 of the hanger body15, such upper external thread extending to the upper end of the body.The sleeve 25 is swivelly connected to an upper abutment ring 29 thatengages an elastomer packing element 30, which, in turn, engages a lowerabutment ring 31. The swivel connection 32 between the sleeve 25 andupper abutment ring 29, and the structural and functional relationshipbetween the upper abutment ring, packing element 30 and lower abutmentring 31, by themselves form no part of the present invention and areillustrated and described in detail in US. Pat. No. 3,492,026. Theswivel connection 32 permits the actuator and coupling sleeve 25 to berotated relative to the upper abutment ring 2?, packing assembly 30 andlower abutment ring 31.

As specifically illustrated, the actuator sleeve 25, swivel 32, andportions of 29, 30, 31 of the seal structure therebelow are laterallyspaced from a reduced diameter portion 33 of the hanger body below itsexternal thread 27 to provide a continuation of the circulation passage,which includes the annulus '21 between the hanger body seal surface 22and the housing seal surface 13. Such flow passage further includes aplurality of ports 34 in the lower portion of the actuator and couplingsleeve 25 below its thread 26 that open through the exterior of thesleeve into the space 35 between the threaded portion of the sleeve andthe cylindrical wall 13 of the wellhead housing 10.

Initially, the seal structure is disposed in the position illustrated inFIG. 1b, in which the bypass or circulating passage is open and in whichthe upper portion of the actuator and coupling sleeve 25 extends abovethe upper end of the casing hanger body 15. This upper portion hasinternal threads 26a that form a continuation of the internal threads 26of the sleeve meshing with the external threads 27 of the body, theupper sleeve portion being in threaded mesh with external threads 36,such as right-hand threads, on a lower inner portion 37 of a runningtool 38, the external threads being provided on an enlargement orexternal flange 39 of the lower running tool portion. This flange abutsor rests upon the upper end 40 of the hanger body 15, a skirt 41depending therefrom within the body and carrying one or more side sealrings 42 thereon sealing against the inner cylindrical wall 43 of thehanger body. To insure that the threads 36 on the lower portion 37 ofthe running tool form a continuation of the external threads 27 on thebody 15, the lower portion of the running tool is maintained in apredetermined circumferential position with respect to the hanger bodyby one or a plurality of locator pins 44 fixed to the running toolflange 39 and extending downwardly into a longitudinal socket or sockets45 in the hanger body and opening through its upper end. By beingthreaded to both the hanger body and the lower portion 37 of the runningtool 38, the actuator and coupling sleeve 25 connects the lower portion37 of the running tool to the hanger body 15, so that the two aremovable longitudinally as a unit, the lower portion 37 of the runningtool being prevented from rotating relative to the hanger body 15 by thelocator pins 44.

The running tool 38 includes an upper outer portion 46 having an upperthreaded box 47 for threadedly attaching it to the lower end of atubular running string 48 extending to the drilling rig (not shown), andby means of which the casing hanger apparatus and the casing string 17hanging therefrom are lowered from the drilling rig, to place the casingstring at its appropriate depth in the well bore, and to bring theterminal portion 18 of the hanger body into engagement with the housingseat 12. The upper portion 46 of the running tool is swivelly connectedto the lower portion 37 of the running tooi, the latter having anexternal flange 49 above an inner flange 50 on the upper portion, suchthat the lower portion of the running tool hangs from its upper portionduring longitudinal movement of the apparatus from the drilling rig. Theouter upper flange 49 is spaced longitudinally a substantial distanceabove the threaded flange portion 39 to permit downward movement of theupper running tool portion 46 along the lower running tool portion 37 inoperating the device, as described hereinbelow. The lower portionincludes a skirt or sleeve 51 extending upwardly from its outer flange49. currying one or a plurality of side seal rings 52 adapted toslidubly seal with the inner cylindrical wall 53 of the outer runningtool portion, this wall portion terminating at a downwardly facingshoulder 54 initially spaced a substantial distance above the outerflange 49 to permit the upper portion 46 to move longitudinally alongthe lower portion 37.

When the lower portion 37 of the running tool is supported by the innerflange 50 of the upper portion, axially extending clutch dogs or teeth55 at the lower end of the upper running tool portion 46 mesh withcompanion upwardly extending teeth 56 at the upper end of the actuatorand coupling sleeve 25 of the'seal structure, the parts being in thecondition illustrated in FIGS. 10, 1b. Rotation of the running string 48and upper portion of the run ring tool 46, as to the right, will rotatethe actuator and coupling sleeve 25 with respect to the threaded flangeor head 39 of the lower portion of the running tool 37 and with respectto the casing hanger body 15 to feed the seal structure 24 downwardly,and to move the seal portion 30 into the annulus 21 between the sealsurfaces 22, 13, also bring the lower abutment 31 into engagement withthe upwardly facing seat or shoulder 23. Before the seal is effectedbetween the opposed seal surfaces 22, 13, the coupling sleeve 25 willhave been threaded downwardly completely off the threaded head 39 of thelower portion 37 of the running tool. When the lower abutment engagesthe seat 23, rotation of the sleeve 25 by the upper portion 46 of therunning tool will move the upper abutment 29 toward the lower abutmentand compress the packing element 30 therebetween, expanding it bothinwardly and outwardly into firm sealing engagement with the externalseal surface 22 and the internal seal surface 13, thereby closing thecirculation passage 20, 19, 21, 34, 35. Rotation of the actuator sleeve25 occurs without rotating the upper abutment ring 29, packing element30 and lower abutment 31 because of the swivel connection 32therebetween.

in the use of the apparatus, the casing string 17 is lowered from thedrilling rig through the wellhead housing 10 and into the well bore.When the uppermost casing string section is at the drilling rig, thehanger body 15 is threadedly secured thereto and the seal structure 24threadedly mounted on the body. It is also threadedly coupled to thelower portion 37 of the running tool 38, which has been appropriatelylocated with respect to the hanger body 15 by the locator pins 44fitting within the body sockets 45. The outer portion 46 of the runningtoo] is then in appropriate position, with its clutch dogs 55 meshingwith the clutch dogs 56 on the actuator and coupling sleeve 25, theparts then being in the relative position illustrated in FIGS. la, 1b.The running too] is threadedly secured to the casing or other tubularrunning string 48, lowering of the casing i7 in the well bore and of thecasing hanger apparatus and running too] occurring until the apparatus14 moves into the wellhead housing 10 and the lower terminal 18 of thehanger body i5 engages the housing seat 12, the parts then being in thecondition illustrated in FIGS. 1a, 1b. At this time, the circulationpassage is open.

Circulating fluid can now be pumped down the running string 48, thehanger apparatus 14 and into the casing string 17, discharging from itslower end, or at any other desired point through a ported collar (notshown) for upward passage through the annulus 20 surrounding the casingstring, and then through the bypass or circulation passage 19, 21 andinto the wellhead housing 10, flowing around the running tool 38 andupwardly through the annulus surrounding the running string 48 back tothe drilling rig. After circulation has been completed, the requiredcharge of cement slurry is pumped down the running string 48 and thecasing string 17, flowing out of the casing shoe or other desired point,then passing upwardly through the annulus 20 surrounding the casingstring until it arrives at the circulation passage between the casinghanger and housing.

Immediately upon completion of the operation of pumping the cement intoplace, the running string 48 and upper portion 46 of the running toolare rotated to the right, such right-hand rotation being transmitted tothe actuator nnd coupling sleeve 25, which is threaded downwardly tounscrew it completely off the threaded head 39 of the lower portion 37of the running tool, and to bring the lower abutment 31 into engagementwith the shoulder 23 and then to effect movement of the upper abutment29 toward the lower abutment 31 and compression of the elastomer packingelement 30 between the outer and inner seal surfaces 22, 13, therebyclosing the circulation passage. The casing string 17 prevents turningof the casing hanger body and of the lower portion 37 of the runningtool pinned thereto, insuring the appropriate downward threading of theactuator sleeve and of the packing structure swivelly carried thereby toits sealed position. When the seal has been completed against the sealsurfaces 22, 21, it will be noted that the upper end of the actuator andcoupling sleeve 25 is disposed substantially below the upper end of thecasing hanger body 15, exposing a plurality of thread turns (FIGS. 2a,2b).

With the pack-off completed, the blowout preventer (not shown) can beclosed on the running string 48 and pressure applied through the chokeor kill line (not shown) to the annular space 35 between the casinghanger body and wellhead housing to test the seal and to assure that itdoes not leak. If leakage occurs, additional torque can be transmittedfrom the running string 48 and running tool 38 to the actuator sleeve 25to apply a greater longitudinal compressive force to the packing elementto stop the leak.

The blowout preventer can then be opened and the running string 48elevated to elevate the upper portion 46 of the running tool along itslower portion 37 and to bring the inner flange 50 into engagement withthe outer flange 49 which will then lift the lower portion 37 of therunning tool out of the casing hanger body 15, the running tool 38 andcasing string 48 then being elevated to the drilling rig, leaving theparts in the condition illustrated in FIG. 3.

A seat protector or wear bushing (not shown) may then be located in thewellhead housing to protect its inner cylindrical wall 13, and drillingof the well continued through the casing string 17.

If desired, additional casing hanger assemblies 14a, 1412 can be locatedin the wellhead housing, each assembly supporting its casing string 17a,17b, of an appropriate diameter, and being installed after the well borehas been drilled ahead to the desired depth. Each assembly is lowered ona running string and running tool and seated on the upper end of apreviously installed casing hanger, after which each seal assembly isrotated to place it in its sealed position against the seal surfaces 22,13, closing the circulation ports of its casing hanger body. Asdisclosed in FIGS. 4a, 4b, a casing hanger body 15a is landed on apreviously installed casing hanger body 15, being centered with respectthereto by a depending centering rib 100 piloted within the upperportion of the lower casing hanger body 15, the centering rib having adownwardly tapering surface 101, engaging a companion tapered surface102 on the upper end of the lower hanger body 15.

As disclosed by way of example in FIG. 4a, a third casing hangerassembly 1411 has been installed in the well bore and is centered in theintermediate body 15a by means of its depending rib 100 engaging acompanion tapered surface 102 at the upper end of the hanger body, theseal structure 24 on the uppermost casing hanger body 15b having beenlowered and sealed against the surfaces 22, 13, to closethe circulationpath after the casing string 1711 has been appropriately cemented inplace.

Each casing hanger body has an internal flange 60 provided with adownwardly tapering shoulder 61 on which a tubing hanger T is adapted tocome to rest. in general, the tubing hanger is of a known specificdesign, including a main body 62 having a circumferential groove 63 inits upper portion and into which latch elements of a running tool (notshown) may be retained for lowering the tubing hanger and a string oftubing 64 secured to its lower threaded box 65 in the well bore and inthe casing hanger assembly 14b. The tubing hanger will be supported bythe internal shoulder or seat 61 of the uppermost casing hanger body15b. As disclosed, a lower abutment 66 having a downwardly taperingsurface is adapted to engage this seat, this abutment being preventedfrom dropping downwardly along the body to any substantial extent by asplit snap retainer ring 67 disposed in an external groove 68 in thebody. An elastomer seal ring 69 rests upon the abutment ring, its upperend being engageable with a downwardly facing body shoulder 70. Thetubing hanger body portion 71 above the seal ring and the abutment ringhas a diameter closely approximating the inside diameter of the casinghanger body above its shoulder, the seal ring also having approximatelythe same diameter, or slightly less than the [.D. of the body wall 72.The casing hanger body has an outwardly directed head or flange 73overlying the casin hanger body and provided with a depending centeringrib 74 adapted to engage a companion downwardly tapering surface 102 atthe upper end of the easing hanger body 15b.

Extending upwardly from the outer portion of its flange 73, the bodycomprises a sleeve portion 75 encircled by a coupling sleeve 76 having alower internally threaded skirt 77 adapted to mesh with the exposed bodythreads 27. The coupling sleeve 76 has a downwardly facing shoulder 78adapted to engage an upwardly facing shoulder 79 on the flangeexternally of its upwardly projecting sleeve portion 75, so as to clampthe flange 73 and the tubular hanger body 62 between the coupling sleeveshoulder 78 and the upper portion of the casing hanger body 15b, as aresult of rotation of the coupling sleeve in the right-hand direction tomesh its skirt portion 77 with the external threads 27 on the upperportion of the'hanger body 15!; and thread it downwardly therealong toeffect the clamping and retaining action of the tubing hanger body 62against the casing hanger body 15b. Rotation of the coupling sleeve ornut 76 is performed by a suitable tool (not shown) which has projectionsfitting into axial recesses 80 opening through the upper end of thecoupling nut, after the tubing hanger body has been landed on the casinghanger body 1512. When such landing occurs, the abutment 66 comes torest upon the hanger body shoulder 61, the tubing hanger body thenmoving downwardly to a slight extent to compress the seal ring 69between the inner wall 72 of the casing hanger body and the opposedcylindrical external surface of the tubing hanger body 62.

The coupling nut 76 may be slipped over the tubular hanger body, withits lower shoulder 78 engaging a split retainer ring 82 located in anexternal groove 83 in the upper portion of the sleeve 75, the shoulder75 contracting and riding past the ring, which will then snap into anelongate circumferential groove 84 in the coupling sleeve above itsshoulder 78. The coupling sleeve cannot move upwardly off the tubinghanger body by virtue of engagement of its shoulder with the retainerring 82. However, such retainer ring 82 does not interfere with downwardfeeding ofthe coupling sleeve member 76 along the tubular hanger body 62upon being threadedly meshed with the casing hanger body threads 27.

The specific type of tubing hanger T forms no part of the presentinvention. As disclosed, it includes a valve sleeve 85 disposedtherewithin adapted to be releasably retained in a lower position by asuitable spring 86 on the valve sleeve engaged within an internal groove87 in the hanger body, in which fluid can flow through the space 88surrounding the hanger body into ports 89 above an intermediate sealassembly 90 on the valve sleeve and then into longitudinal passages 91in the hanger body opening through its upper end. The valve sleeve hasan upper seal assembly 92 engaging the inner wall of the tubing hangerbody 62 above the lower end of the upper passages 91 to confine the flowof fluid to the path just referred to. By means of a suitable tool (notshown) lowered on a wire line from the drilling rig, the sleeve 85 canbe pulled upwardly, its spring 86 being forced out of its companiongroove 87, the sleeve being moved upwardly within the body until theintermediate seal 90 is disposed above the lower tubing hanger bodyports 89 and a lower seal 93 is disposed in sealed relation against thetubing hanger body below the ports, thereby closing such ports to theflow of fluid. The valve sleeve is releasably retained in this upperposition by virtue of its spring 86 snapping into an upper internalgroove 94 in the hanger body.

It is apparent that the same threaded portion 27 of the hanger body usedfor connecting the running tool thereto, and for effecting longitudinalshifting of the seal structure 24 between circulation path opening andclosing positions, is used for locking the tubing hanger body 62dovmwardly in the casing hanger body 15b.

It is apparent that a casing hanger apparatus has been provided, inwhich, regardless of the size of casing string to be suspendedtherefrom, the exterior of the casing hanger body and the seal structureused in connection therewith is identical, which makes it necessary toprovide only one size and type of seal structure 24. The casing hangerbodies vary from one another only in connection with their insideprofile and the threaded box 16 to which the suspended casing string issecured. Thus, inventory problems are greatly simplified, as well aseconomies of manufacture. The apparatus itself is much simpler thanprior devices, while it is still capable of withstanding high fluidpressures. Bypass grooves and ports in the wellhead housing areeliminated, since the wellhead housing above its lower seat provides acontinuous cylindrical sealing surface 13. The running too] 38 is ofcomparatively simple construction and of mode of operation, being lesscostly to manufacture. In this connection, it is to be noted that therunning tool has been illustrated in partially diagrammatic fashion, inorder to simplify the illustration. It is evident that suitable jointswould be provided to facilitate assembly of the upper and lower portions46, 37 of the running tool with respect to one another.

Iclaim:

1. In well bore casing apparatus: an outer body having a seat therein;an inner body for suspending a tubular string in a well bore and movableinto engagement with said seat; passage means for allowing fluid flowbetween said inner and outer bodies; a seal structure on said innerbody; first means for connecting said seal structure to the exterior ofsaid inner body, whereby rotation of said seal structure moves said sealstructure longitudinally along said inner body to a position closingsaid passage means; a running tool connectable to a running string;second means for releasably connecting said running tool to said sealstructure to support said seal structure and inner body from saidrunning too] and thereby enable said running tool and the running stringto lower said inner body and seal structure as a unit into said outerbody; and third means for transmitting rotary motion of said runningstring to said seal structure to disconnect said second means and movesaid seal structure to its position closing said passage means.

2. In apparatus as defined in claim 1; said first means comprising athreaded connection between said seal structure and inner body.

3. In apparatus as defined in claim 1; said second means comprising athreaded connection between said seal structure and running tool.

4. In apparatus as defined in claim 1; said first means com prising anexternal thread on said inner body and a first internal thread portionon said seal structure meshing with said external thread; said secondmeans comprising an external thread on said running tool and a secondinternal thread portion on said seal structure meshing therewith;rotation of said seal structure by said running too] unscrewing saidsecond internal thread portion from said running tool and moving saidseal structure to its position closing said passage means.

5. In apparatus as defined in claim 1; said first means comprising anexternal thread on said inner body and a first internal thread portionon said seal structure meshing with said external thread; said secondmeans comprising an external thread on said running tool and a secondinternal thread portion on said seal structure meshing therewith;rotation of said seal structure by said running too] unscrewing saidsecond internal thread portion from said running too! and moving saidseal structure to its position closing said passage means; said thirdmeans comprising clutch means on said running tool meshing with clutchmeans on said seal structure.

6. In apparatus as defined in claim 1; said first means comprising anexternal thread on said inner body and an internal thread on said sealstructure meshing with said external thread; said second meanscomprising an external thread on said running tool meshing with saidinternal thread; rotation of said seal structure by said running toolunscrewing said internal thread from said running tool and moving saidseal struc ture to its position closing said passage means.

7. In apparatus as defined in claim 1; said first means comprising anexternal right-hand thread on said inner body and an internal right-hand.nread on said seal structure meshing with said external thread; saidsecond means comprising an external right-hand thread on said runningtoo] meshing with said internal thread; right-hand rotation of said sealstructure by said running tool unscrewing said internal thread from saidrunning tool and moving said seal structure downwardly along said innerbody to its position closing said passage means.

8. In apparatus as defined in claim 1; said first means comprising anexternal right-hand thread on said inner body and an internal right-handthread on said seal structure meshing with said external thread; saidsecond means comprising an external right-hand thread on said runningtool meshing with said internal thread; right-hand rotation of said sealstructure by said running tool unscrewing said internal thread from saidrunning tool and moving said seal structure downwardly along said innerbody to its position closing said passage means; said third meanscomprising clutch means on said running tool meshing with clutch meanson said seal structure for transmitting rotary motion of said runningtoo] to said seal structure.

9. In well bore casing apparatus: an outer body having a seat therein;an inner body for suspending a tubular string in a well bore and movableinto engagement with said seat; passage means for allowing fluid flowbetween said inner and outer bodies; a seal structure on said innerbody; first means for connecting said seal structure to the exterior ofsaid inner body, whereby rotation of said seal structure moves said sealstructure longitudinally along said inner body to a position closingsaid passage means; a running tool comprising a first portionconnectable to a running string and a second portion swivelly related tosaid first portion; second means for releasably connecting said secondportion to said seal structure; and third means for transmitting rotarymotion of said first portion to said seal structure to disconnect saidsecond means and move said seal structure to its position closing saidpassage means.

10. In apparatus as defined in claim 9; said first means comprising athreaded connection between said seal structure and inner body.

11. In apparatus as defined in claim 9; said second means comprising athreaded connection between said seal structure and said second portionof said running too].

12. In apparatus as defined in claim 9; said first means comprising anexternal thread on said inner body and a first internal thread portionon said seal structure meshing with said external thread; said secondmeans comprising an external thread on said second portion of saidrunning tool and a second internal thread portion on said seal structuremeshing therewith; rotation of said seal structure by said first portionof said running tool unscrewing said second internal thread portion fromsaid second portion of said running tool and moving said seal structureto its position closing said passage means.

13. In apparatus as defined in claim 9; said first means comprising anexternal thread on said inner body and a first internal thread portionon said seal structure meshing with said external thread; said secondmeans comprising an external thread on said second portion of saidrunning tool and a second internal thread portion on said seal structuremeshing therewith; rotation of said seal structure by said first portionof said running tool unscrewing said second internal thread por tionfrom said second portion of said running tool and moving said sealstructure to its position closing said passage means;

said third means comprising clutch means on said first portion of saidrunning tool meshing with clutch means on said seal structure.

14. In apparatus as defined in claim 9; said first means comprising anexternal thread on said inner body and an internal thread on said sealstructure meshing with said external thread; said second meanscomprising an external thread on said second portion of said runningtool meshing with said internal thread; rotation of said seal structureby said first portion of said running tool unscrewing said internalthread from said second portion of said running tool and moving saidseal structure to its position closing said passage means.

15. In apparatus as defined in claim 9; said first means comprising anexternal right-hand thread on said inner body and an internal right-handthread on said seal structure meshing with said external thread; saidsecond means comprising an external right-hand thread on said secondportion of said running tool meshing with said internal thread;right-hand 'rotation of said seal structure by said first portion ofsaid running tool unscrewing said internal thread from said firstportion of said running tool and moving said seal structure downwardlyalong said inner body to its position closing said passage means.

16. In apparatus as defined in claim 9; said first means comprising anexternal right-hand thread on said inner body and an internal right-handthread on said seal structure meshing with said external thread; saidsecond means comprising an external right-hand thread on said secondportion of said running too] meshing with said internal thread;right-hand rotation of said seal structure by said first portion of saidrunning tool unscrewing said internal thread from said first portion ofsaid running tool and moving said seal structure downwardly along saidinner body to its position closing said passage means; said third meanscomprising clutch means on said first portion of said running toolmeshing with clutch means on said seal structure.

1. In well bore casing apparatus: an outer body having a seat therein;an inner body for suspending a tubular string in a well bore and movableinto engagement with said seat; passage means for allowing fluid flowbetween said inner and outer bodies; a seal structure on said innerbody; first means for connecting said seal structure to the exterior ofsaid inner body, whereby rotation of said seal structure moves said sealstructure longitudinally along said inner body to a position closingsaid passage means; a running tool connectable to a running string;second means for releasably connecting said running tool to said sealstructure to support said seal structure and inner body from saidrunning tool and thereby enable said running tool and the running stringto lower said inner body and seal structure as a unit into said outerbody; and third means for transmitting rotary motion of said runningstring to said seal structure to disconnect said second means and movesaid seal structure to its position closing said passage means.
 2. Inapparatus as defined in claim 1; said first means comprising a threadedconnection between said seal structure and inner body.
 3. In apparatusas defined in claim 1; said second means comprising a threadedconnection between said seal structure and running tool.
 4. In apparatusas defined in claim 1; said first means comprising an external thread onsaid inner body and a first internal thread portion on said sealstructure meshing with said external thread; said second meanscomprising an external thread on said running tool and a second internalthread portion on said seal structure meshing therewith; rotation ofsaid seal structure by said running tool unscrewing said second internalthread portion from said running tool and moving said seal structure toits position closing said passage means.
 5. In apparatus as defined inclaim 1; said first means comprising an external thread on said innerbody and a first internal thread portion on said seal structure meshingwith said external thread; said second means comprising an externalthread on said running tool and a second internal thread portion on saidseal structure meshing therewith; rotation of said seal structure bysaid running tool unscrewing said second internal thread portion fromsaid running tool and moving said seal structure to its position closingsaid passage means; said third means comprising clutch means on saidrunning tool meshing with clutch means on said seal structure.
 6. Inapparatus as defined in claim 1; said first means comprising an externalthread on said inner body and an internal thread on said seal structuremeshing with said external thread; said second means comprising anexternal thread on said running tool meshing with said internal thread;rotation of said seal structure by said running tool unscrewing saidinternal thread from said running tool and moving said seal structure toits position closing said passage means.
 7. In apparatus as defined inClaim 1; said first means comprising an external right-hand thread onsaid inner body and an internal right-hand thread on said seal structuremeshing with said external thread; said second means comprising anexternal right-hand thread on said running tool meshing with saidinternal thread; right-hand rotation of said seal structure by saidrunning tool unscrewing said internal thread from said running tool andmoving said seal structure downwardly along said inner body to itsposition closing said passage means.
 8. In apparatus as defined in claim1; said first means comprising an external right-hand thread on saidinner body and an internal right-hand thread on said seal structuremeshing with said external thread; said second means comprising anexternal right-hand thread on said running tool meshing with saidinternal thread; right-hand rotation of said seal structure by saidrunning tool unscrewing said internal thread from said running tool andmoving said seal structure downwardly along said inner body to itsposition closing said passage means; said third means comprising clutchmeans on said running tool meshing with clutch means on said sealstructure for transmitting rotary motion of said running tool to saidseal structure.
 9. In well bore casing apparatus: an outer body having aseat therein; an inner body for suspending a tubular string in a wellbore and movable into engagement with said seat; passage means forallowing fluid flow between said inner and outer bodies; a sealstructure on said inner body; first means for connecting said sealstructure to the exterior of said inner body, whereby rotation of saidseal structure moves said seal structure longitudinally along said innerbody to a position closing said passage means; a running tool comprisinga first portion connectable to a running string and a second portionswivelly related to said first portion; second means for releasablyconnecting said second portion to said seal structure; and third meansfor transmitting rotary motion of said first portion to said sealstructure to disconnect said second means and move said seal structureto its position closing said passage means.
 10. In apparatus as definedin claim 9; said first means comprising a threaded connection betweensaid seal structure and inner body.
 11. In apparatus as defined in claim9; said second means comprising a threaded connection between said sealstructure and said second portion of said running tool.
 12. In apparatusas defined in claim 9; said first means comprising an external thread onsaid inner body and a first internal thread portion on said sealstructure meshing with said external thread; said second meanscomprising an external thread on said second portion of said runningtool and a second internal thread portion on said seal structure meshingtherewith; rotation of said seal structure by said first portion of saidrunning tool unscrewing said second internal thread portion from saidsecond portion of said running tool and moving said seal structure toits position closing said passage means.
 13. In apparatus as defined inclaim 9; said first means comprising an external thread on said innerbody and a first internal thread portion on said seal structure meshingwith said external thread; said second means comprising an externalthread on said second portion of said running tool and a second internalthread portion on said seal structure meshing therewith; rotation ofsaid seal structure by said first portion of said running toolunscrewing said second internal thread portion from said second portionof said running tool and moving said seal structure to its positionclosing said passage means; said third means comprising clutch means onsaid first portion of said running tool meshing with clutch means onsaid seal structure.
 14. In apparatus as defined in claim 9; said firstmeans comprising an external thread on said inner body and an internalthread on said seal structure meshing with said external Thread; saidsecond means comprising an external thread on said second portion ofsaid running tool meshing with said internal thread; rotation of saidseal structure by said first portion of said running tool unscrewingsaid internal thread from said second portion of said running tool andmoving said seal structure to its position closing said passage means.15. In apparatus as defined in claim 9; said first means comprising anexternal right-hand thread on said inner body and an internal right-handthread on said seal structure meshing with said external thread; saidsecond means comprising an external right-hand thread on said secondportion of said running tool meshing with said internal thread;right-hand rotation of said seal structure by said first portion of saidrunning tool unscrewing said internal thread from said first portion ofsaid running tool and moving said seal structure downwardly along saidinner body to its position closing said passage means.
 16. In apparatusas defined in claim 9; said first means comprising an externalright-hand thread on said inner body and an internal right-hand threadon said seal structure meshing with said external thread; said secondmeans comprising an external right-hand thread on said second portion ofsaid running tool meshing with said internal thread; right-hand rotationof said seal structure by said first portion of said running toolunscrewing said internal thread from said first portion of said runningtool and moving said seal structure downwardly along said inner body toits position closing said passage means; said third means comprisingclutch means on said first portion of said running tool meshing withclutch means on said seal structure.